feat(build): multiple build targets per package

is-child can be passed as argument to wasm-pack build for generating
packages with multiple build targets

Author: Tarnadas

docs/src/commands/build.md

@@ -125,6 +125,23 @@ wasm-pack build examples/js-hello-world --mode no-install
 | `no-install`  | `wasm-pack init` implicitly and create wasm binding  without installing `wasm-bindgen`.  |
 | `normal`      | do all the stuffs of `no-install` with installed `wasm-bindgen`.                         |
 
+## Multiple build targets per package
+
+The `build` command accepts an optional `--is-child` argument.
+```
+wasm-pack build examples/js-hello-world --is-child --out-name child
+```
+
+This command will extend a previously generated package, which makes it possible to have multiple build targets per package.
+For example it would be feasible to have an optimized build for web and Node.
+
+Following is an example which will use the wee_alloc feature for web, because size is more crucial whereas Node should be optimized for speed.
+
+```
+wasm-pack build examples/js-hello-world --out-dir pkg -- --features "wee_alloc"
+wasm-pack build examples/js-hello-world --out-dir pkg --out-name js-hello-node --is-child
+```
+
 ## Extra options
 
 The `build` command can pass extra options straight to `cargo build` even if they are not

src/command/build.rs

@@ -32,6 +32,7 @@ pub struct Build {
     pub mode: InstallMode,
     pub out_dir: PathBuf,
     pub out_name: Option<String>,
+    pub is_child: bool,
     pub bindgen: Option<install::Status>,
     pub cache: Cache,
     pub extra_options: Vec<String>,
@@ -148,6 +149,10 @@ pub struct BuildOptions {
     /// Sets the output file names. Defaults to package name.
     pub out_name: Option<String>,
 
+    #[structopt(long = "is-child")]
+    /// Won't generate package metadata. Instead adds output to existing package given by `out-dir`.
+    pub is_child: bool,
+
     #[structopt(last = true)]
     /// List of extra options to pass to `cargo build`
     pub extra_options: Vec<String>,
@@ -167,6 +172,7 @@ impl Default for BuildOptions {
             profiling: false,
             out_dir: String::new(),
             out_name: None,
+            is_child: false,
             extra_options: Vec::new(),
         }
     }
@@ -201,6 +207,7 @@ impl Build {
             mode: build_opts.mode,
             out_dir,
             out_name: build_opts.out_name,
+            is_child: build_opts.is_child,
             bindgen: None,
             cache: cache::get_wasm_pack_cache()?,
             extra_options: build_opts.extra_options,
@@ -324,6 +331,7 @@ impl Build {
             &self.scope,
             self.disable_dts,
             self.target,
+            self.is_child,
         )?;
         info!(
             "Wrote a package.json at {:#?}.",
@@ -333,13 +341,19 @@ impl Build {
     }
 
     fn step_copy_readme(&mut self) -> Result<(), Error> {
+        if self.is_child {
+            return Ok(());
+        }
         info!("Copying readme from crate...");
         readme::copy_from_crate(&self.crate_path, &self.out_dir)?;
         info!("Copied readme from crate to {:#?}.", &self.out_dir);
         Ok(())
     }
 
     fn step_copy_license(&mut self) -> Result<(), failure::Error> {
+        if self.is_child {
+            return Ok(());
+        }
         info!("Copying license from crate...");
         license::copy_from_crate(&self.crate_data, &self.crate_path, &self.out_dir)?;
         info!("Copied license from crate to {:#?}.", &self.out_dir);

src/manifest/mod.rs

@@ -573,13 +573,43 @@ impl CrateData {
         scope: &Option<String>,
         disable_dts: bool,
         target: Target,
+        is_child: bool,
     ) -> Result<(), Error> {
         let pkg_file_path = out_dir.join("package.json");
-        let npm_data = match target {
-            Target::Nodejs => self.to_commonjs(scope, disable_dts, out_dir),
-            Target::NoModules => self.to_nomodules(scope, disable_dts, out_dir),
-            Target::Bundler => self.to_esmodules(scope, disable_dts, out_dir),
-            Target::Web => self.to_web(scope, disable_dts, out_dir),
+        let npm_data = if is_child {
+            let npm_json = match fs::read_to_string(&pkg_file_path) {
+                Ok(file) => file,
+                Err(_) => bail!(
+                    "--is-child was provided, but given --out-dir path does not contain a package.json. \
+                     Please make sure, that you compile the parent directory to the same --out-dir"),
+            };
+            let mut npm_data: NpmPackage = serde_json::from_str(&npm_json)?;
+            let name_prefix = self.name_prefix();
+
+            let wasm_file = format!("{}_bg.wasm", name_prefix);
+            npm_data.add_file(wasm_file);
+
+            let js_file = format!("{}.js", name_prefix);
+            npm_data.add_file(js_file);
+
+            if let Target::Nodejs = target {
+                let js_bg_file = format!("{}_bg.js", name_prefix);
+                npm_data.add_file(js_bg_file);
+            }
+
+            if !disable_dts {
+                let dts_file = format!("{}.d.ts", name_prefix);
+                npm_data.add_file(dts_file);
+            }
+
+            npm_data
+        } else {
+            match target {
+                Target::Nodejs => self.to_commonjs(scope, disable_dts, out_dir),
+                Target::NoModules => self.to_nomodules(scope, disable_dts, out_dir),
+                Target::Bundler => self.to_esmodules(scope, disable_dts, out_dir),
+                Target::Web => self.to_web(scope, disable_dts, out_dir),
+            }
         };
 
         let npm_json = serde_json::to_string_pretty(&npm_data)?;

src/manifest/npm/commonjs.rs

@@ -1,6 +1,6 @@
 use manifest::npm::repository::Repository;
 
-#[derive(Serialize)]
+#[derive(Deserialize, Serialize)]
 pub struct CommonJSPackage {
     pub name: String,
     #[serde(skip_serializing_if = "Vec::is_empty")]

src/manifest/npm/esmodules.rs

@@ -1,6 +1,6 @@
 use manifest::npm::repository::Repository;
 
-#[derive(Serialize)]
+#[derive(Deserialize, Serialize)]
 pub struct ESModulesPackage {
     pub name: String,
     #[serde(skip_serializing_if = "Vec::is_empty")]

src/manifest/npm/mod.rs

@@ -7,10 +7,20 @@ pub use self::commonjs::CommonJSPackage;
 pub use self::esmodules::ESModulesPackage;
 pub use self::nomodules::NoModulesPackage;
 
-#[derive(Serialize)]
+#[derive(Deserialize, Serialize)]
 #[serde(untagged)]
 pub enum NpmPackage {
     CommonJSPackage(CommonJSPackage),
     ESModulesPackage(ESModulesPackage),
     NoModulesPackage(NoModulesPackage),
 }
+
+impl NpmPackage {
+    pub fn add_file(&mut self, file: String) {
+        match self {
+            Self::CommonJSPackage(pkg) => pkg.files.push(file),
+            Self::ESModulesPackage(pkg) => pkg.files.push(file),
+            Self::NoModulesPackage(pkg) => pkg.files.push(file),
+        }
+    }
+}

src/manifest/npm/nomodules.rs

@@ -1,6 +1,6 @@
 use manifest::npm::repository::Repository;
 
-#[derive(Serialize)]
+#[derive(Deserialize, Serialize)]
 pub struct NoModulesPackage {
     pub name: String,
     #[serde(skip_serializing_if = "Vec::is_empty")]

src/manifest/npm/repository.rs

@@ -1,4 +1,4 @@
-#[derive(Serialize)]
+#[derive(Deserialize, Serialize)]
 pub struct Repository {
     #[serde(rename = "type")]
     pub ty: String,

tests/all/manifest.rs

@@ -79,7 +79,7 @@ fn it_creates_a_package_json_default_path() {
     let crate_data = manifest::CrateData::new(&fixture.path, None).unwrap();
     wasm_pack::command::utils::create_pkg_dir(&out_dir).unwrap();
     assert!(crate_data
-        .write_package_json(&out_dir, &None, false, Target::Bundler)
+        .write_package_json(&out_dir, &None, false, Target::Bundler, false)
         .is_ok());
     let package_json_path = &fixture.path.join("pkg").join("package.json");
     fs::metadata(package_json_path).unwrap();
@@ -115,7 +115,7 @@ fn it_creates_a_package_json_provided_path() {
     let crate_data = manifest::CrateData::new(&fixture.path, None).unwrap();
     wasm_pack::command::utils::create_pkg_dir(&out_dir).unwrap();
     assert!(crate_data
-        .write_package_json(&out_dir, &None, false, Target::Bundler)
+        .write_package_json(&out_dir, &None, false, Target::Bundler, false)
         .is_ok());
     let package_json_path = &fixture.path.join("pkg").join("package.json");
     fs::metadata(package_json_path).unwrap();
@@ -144,7 +144,13 @@ fn it_creates_a_package_json_provided_path_with_scope() {
     let crate_data = manifest::CrateData::new(&fixture.path, None).unwrap();
     wasm_pack::command::utils::create_pkg_dir(&out_dir).unwrap();
     assert!(crate_data
-        .write_package_json(&out_dir, &Some("test".to_string()), false, Target::Bundler,)
+        .write_package_json(
+            &out_dir,
+            &Some("test".to_string()),
+            false,
+            Target::Bundler,
+            false
+        )
         .is_ok());
     let package_json_path = &fixture.path.join("pkg").join("package.json");
     fs::metadata(package_json_path).unwrap();
@@ -173,7 +179,7 @@ fn it_creates_a_pkg_json_with_correct_files_on_node() {
     let crate_data = manifest::CrateData::new(&fixture.path, None).unwrap();
     wasm_pack::command::utils::create_pkg_dir(&out_dir).unwrap();
     assert!(crate_data
-        .write_package_json(&out_dir, &None, false, Target::Nodejs)
+        .write_package_json(&out_dir, &None, false, Target::Nodejs, false)
         .is_ok());
     let package_json_path = &out_dir.join("package.json");
     fs::metadata(package_json_path).unwrap();
@@ -207,7 +213,7 @@ fn it_creates_a_pkg_json_with_correct_files_on_nomodules() {
     let crate_data = manifest::CrateData::new(&fixture.path, None).unwrap();
     wasm_pack::command::utils::create_pkg_dir(&out_dir).unwrap();
     assert!(crate_data
-        .write_package_json(&out_dir, &None, false, Target::NoModules)
+        .write_package_json(&out_dir, &None, false, Target::NoModules, false)
         .is_ok());
     let package_json_path = &out_dir.join("package.json");
     fs::metadata(package_json_path).unwrap();
@@ -241,7 +247,7 @@ fn it_creates_a_package_json_with_correct_files_when_out_name_is_provided() {
     let crate_data = manifest::CrateData::new(&fixture.path, Some("index".to_owned())).unwrap();
     wasm_pack::command::utils::create_pkg_dir(&out_dir).unwrap();
     assert!(crate_data
-        .write_package_json(&out_dir, &None, false, Target::Bundler)
+        .write_package_json(&out_dir, &None, false, Target::Bundler, false)
         .is_ok());
     let package_json_path = &fixture.path.join("pkg").join("package.json");
     fs::metadata(package_json_path).unwrap();
@@ -273,7 +279,7 @@ fn it_creates_a_pkg_json_in_out_dir() {
     let crate_data = manifest::CrateData::new(&fixture.path, None).unwrap();
     wasm_pack::command::utils::create_pkg_dir(&out_dir).unwrap();
     assert!(crate_data
-        .write_package_json(&out_dir, &None, false, Target::Bundler)
+        .write_package_json(&out_dir, &None, false, Target::Bundler, false)
         .is_ok());
 
     let package_json_path = &fixture.path.join(&out_dir).join("package.json");
@@ -288,7 +294,7 @@ fn it_creates_a_package_json_with_correct_keys_when_types_are_skipped() {
     let crate_data = manifest::CrateData::new(&fixture.path, None).unwrap();
     wasm_pack::command::utils::create_pkg_dir(&out_dir).unwrap();
     assert!(crate_data
-        .write_package_json(&out_dir, &None, true, Target::Bundler)
+        .write_package_json(&out_dir, &None, true, Target::Bundler, false)
         .is_ok());
     let package_json_path = &out_dir.join("package.json");
     fs::metadata(package_json_path).unwrap();
@@ -314,13 +320,73 @@ fn it_creates_a_package_json_with_correct_keys_when_types_are_skipped() {
     assert_eq!(actual_files, expected_files);
 }
 
+#[test]
+fn it_creates_a_package_json_with_correct_files_when_is_child_is_provided() {
+    let fixture = fixture::js_hello_world();
+    let out_dir = fixture.path.join("pkg");
+    let crate_data = manifest::CrateData::new(&fixture.path, Some("index".to_owned())).unwrap();
+    let crate_data_child =
+        manifest::CrateData::new(&fixture.path, Some("child".to_owned())).unwrap();
+    wasm_pack::command::utils::create_pkg_dir(&out_dir).unwrap();
+    assert!(crate_data
+        .write_package_json(&out_dir, &None, false, Target::Web, false)
+        .is_ok());
+    assert!(crate_data_child
+        .write_package_json(&out_dir, &None, false, Target::Web, true)
+        .is_ok());
+    let package_json_path = &fixture.path.join("pkg").join("package.json");
+    fs::metadata(package_json_path).unwrap();
+    utils::manifest::read_package_json(&fixture.path, &out_dir).unwrap();
+    let pkg = utils::manifest::read_package_json(&fixture.path, &out_dir).unwrap();
+    assert_eq!(pkg.name, "js-hello-world");
+    assert_eq!(pkg.repository.ty, "git");
+    assert_eq!(
+        pkg.repository.url,
+        "https://github.com/rustwasm/wasm-pack.git"
+    );
+    assert_eq!(pkg.module, "index.js");
+    assert_eq!(pkg.types, "index.d.ts");
+    assert_eq!(pkg.side_effects, false);
+
+    let actual_files: HashSet<String> = pkg.files.into_iter().collect();
+    let expected_files: HashSet<String> = [
+        "index_bg.wasm",
+        "index.d.ts",
+        "index.js",
+        "child_bg.wasm",
+        "child.d.ts",
+        "child.js",
+    ]
+    .iter()
+    .map(|&s| String::from(s))
+    .collect();
+    assert_eq!(actual_files, expected_files);
+}
+
 #[test]
 fn it_errors_when_wasm_bindgen_is_not_declared() {
     let fixture = fixture::bad_cargo_toml();
     let crate_data = manifest::CrateData::new(&fixture.path, None).unwrap();
     assert!(crate_data.check_crate_config().is_err());
 }
 
+#[test]
+fn it_errors_when_out_dir_of_child_does_not_exist() {
+    let fixture = fixture::js_hello_world();
+    let out_dir = fixture.path.join("pkg");
+    let out_dir_child = fixture.path.join("pkg-child");
+    let crate_data = manifest::CrateData::new(&fixture.path, Some("index".to_owned())).unwrap();
+    let crate_data_child =
+        manifest::CrateData::new(&fixture.path, Some("child".to_owned())).unwrap();
+    wasm_pack::command::utils::create_pkg_dir(&out_dir).unwrap();
+    assert!(crate_data
+        .write_package_json(&out_dir, &None, false, Target::Web, false)
+        .is_ok());
+    assert!(crate_data_child
+        .write_package_json(&out_dir_child, &None, false, Target::Web, true)
+        .is_err());
+}
+
 #[test]
 fn it_sets_homepage_field_if_available_in_cargo_toml() {
     // When 'homepage' is available
@@ -353,7 +419,7 @@ fn it_sets_homepage_field_if_available_in_cargo_toml() {
 
     wasm_pack::command::utils::create_pkg_dir(&out_dir).unwrap();
     crate_data
-        .write_package_json(&out_dir, &None, true, Target::Bundler)
+        .write_package_json(&out_dir, &None, true, Target::Bundler, false)
         .unwrap();
 
     let pkg = utils::manifest::read_package_json(&fixture.path, &out_dir).unwrap();
@@ -369,7 +435,7 @@ fn it_sets_homepage_field_if_available_in_cargo_toml() {
 
     wasm_pack::command::utils::create_pkg_dir(&out_dir).unwrap();
     crate_data
-        .write_package_json(&out_dir, &None, true, Target::Bundler)
+        .write_package_json(&out_dir, &None, true, Target::Bundler, false)
         .unwrap();
 
     let pkg = utils::manifest::read_package_json(&fixture.path, &out_dir).unwrap();
@@ -408,7 +474,7 @@ fn it_sets_keywords_field_if_available_in_cargo_toml() {
 
     wasm_pack::command::utils::create_pkg_dir(&out_dir).unwrap();
     crate_data
-        .write_package_json(&out_dir, &None, true, Target::Bundler)
+        .write_package_json(&out_dir, &None, true, Target::Bundler, false)
         .unwrap();
 
     let pkg = utils::manifest::read_package_json(&fixture.path, &out_dir).unwrap();
@@ -426,7 +492,7 @@ fn it_sets_keywords_field_if_available_in_cargo_toml() {
 
     wasm_pack::command::utils::create_pkg_dir(&out_dir).unwrap();
     crate_data
-        .write_package_json(&out_dir, &None, true, Target::Bundler)
+        .write_package_json(&out_dir, &None, true, Target::Bundler, false)
         .unwrap();
 
     let pkg = utils::manifest::read_package_json(&fixture.path, &out_dir).unwrap();
@@ -527,7 +593,7 @@ fn it_lists_license_files_in_files_field_of_package_json() {
     wasm_pack::command::utils::create_pkg_dir(&out_dir).unwrap();
     license::copy_from_crate(&crate_data, &fixture.path, &out_dir).unwrap();
     crate_data
-        .write_package_json(&out_dir, &None, false, Target::Bundler)
+        .write_package_json(&out_dir, &None, false, Target::Bundler, false)
         .unwrap();
 
     let package_json_path = &fixture.path.join("pkg").join("package.json");